I'm confused by the OP. Are you looking for Sunday sauce or Bolognese? Or Ragu or just meat sauce in general? I would answer differently depending on which one you want, as they are each different.
Sticking with Bolognese, if you are making it yourself Marcella Hazan's recipe is classic and excellent:
After the death in 2013 of Marcella Hazan, the cookbook author who changed the way Americans cook Italian food, The Times asked readers which of her recipes had become staples in their kitchens Many people answered with one word: “Bolognese.” Ms Hazan had a few recipes for the classic sauce, and...
cooking.nytimes.com
If you are looking to get it from a restaurant or store,
Pasta Cosi in Branford has a very good one. I prefer it with their excellent eggplant lasagna.
If you are looking for ragu,
L'Orcio's Papardelle al Ragu is as good as it gets imo.
Portofino and Adriana's, both in New Haven, also have good ones; but I prefer other dishes at each (Portofino also does a very good Sunday sauce with braciole, but I like their Puttanesca best--with swordfish and Angel Hair pasta).
Pasta Vita with several locations throughout the state also sells a good meat sauce.